Human beings communicate ideas with one another using a mechanism known as natural language. Natural language evolved as a medium of communications, as human beings learned to communicate with one another. The specific evolution and structure of our natural language is of little concern to all of us when we speak or write in it. However, due to the inherent structure of natural language, it is an imperfect mechanism for conveying ideas. The human brain, through its intricate and somewhat intuitive workings, translates natural language into concepts and ideas, and allows communications between different individuals using natural language through a complicated translation process that no machine has been able to duplicate.
Machines have no intuitive conceptualization capabilities as of this date (1989). Therefore many difficulties have been encountered in the attempt to teach machines to understand natural language. Machines communicate in languages which were specially invented for the machines and which do not include the ambiguities endemic to natural, evolved languages.
One of the most crucial problems in the artificial intelligence field is the presentation to a machine of the conceptual knowledge behind natural language.
Conceptual knowledge is the knowledge which is known by a human being as a function of semantic meaning. Aristotle had the view (known as the Aristotlean view) that meanings are represented most commonly in concepts which are actualized by words. For instance, when a human being uses the word "chair", the purpose of the word is not to use the actual word itself (e.g. not the letters c.cndot.h.cndot.a.cndot.i.cndot.r), but to denote the meaning of the item (a chair) behind the word "chair". The interpretation of language (such as the word chair) as a whole functions primarily at the conceptual level. That is, in our example we interpret the language which we hear (the compressions and rarefactions of air which comprise the sounds comprising the word "chair.revreaction.) as the item which is represented by the word "chair."
Aristotle's line of reasoning implies that meaning has three elements. The first element is the word itself, which differs from language to language, and even within its own language has inherent ambiguities. For instance, the word "chair" as a noun may mean a seat, a chair rail, or a chair lift, or as a verb, may infer leadership, e.g., to chair a committee, for instance. The second level are the mental images of concepts in the mind, which are signified by the word which are the same for all people. The concepts, for instance, are those which the listener develops when he hears the word "chair". The third element is the concept itself, which is the chair itself, and is the same for all people.
The second and third elements, the concepts and the things themselves, were believed by Aristotle to be the same for all people. It is only the words which differ.
Moreover, the concepts and the things themselves are totally unambiguous, while most words in natural language are ambiguous.